Electric clock



L. DORFMAN.

ELECTRIC CLOCK.

APPLICATION FILED JAN. 301 1920.

1,408,274, Patented Feb. 28, 1922.

2 SHEETSSHEET l.

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ELECTRIC CLOCK.

APPLICATION FILED JAN. 30, 1920;

1,40 ,274, Patented Feb. 28, 1922.

MIN

' ATTORNEY UNITED STATES LEO DOREMAN, OE WILKINSBUBG, PENNSYLVANIA.

ELEGTRIG 610GB.

Specification of Zetters Patent.

Patented Feb. 28, 1922.

Application filed January 30, 1826. Fierial No. 855,233.

To all whom it may concern:

Be it known that I, LEO DORFMAN, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Electric Clocks, of which the following is a specification.

My invention relates to clocks and particularly to electric clocks and to systems wherein such clocks may be employed.

One object of my invention is toprov de an escapement device the period of WhlCh shall be constant, irrespective of the actuating force.

Another object of my invention is to provide a device of the above indicated character for a clock that shall be actuated by a I motor energized from a commercial alternating-current circuit and that shall be constant in speed, irrespective of changes effected 1n the torque of the motor by changes 1n the voltage or in the frequency of the circult.

Another object of my invention is toprovide a device of the above indicated character that shall be simple and rugged in its construction and effective and reliable in its operation.

In the ordinary time-keeping device an oscillating member and an escapement device, comprising an escapement lever and an escapement wheel, are employed for obtaining definite, constant time intervals, at the termination of which the indicating elements are actuated. The driving force is ordina g rily obtained by means of a spring that may be wound or by means of a weight that may be actuated, by gravity, to energize the oscillating member. The oscillating member by means of the escapement lever, so actuates the escapement wheel and a suitable train of gears through the escapement wheel, as to obtain the indications desired. In order that the rate of movement of the indicating mechdriving member in order to keep the period of the oscillating member constant. The frictional losses for each oscillation of the oscillating member are fairly constant, and, in order to maintain the period of theoscillatmg member constant, a definite amount of energy must be periodically supplied to the oscillating member at a definite point in its oscillation.

In view of the frictional losses encountered by the oscillating member, I provide an energy-storm means adapted to periodically transmit a definite amount of energy to the oscillating member to compensate for these losses. Instead of actuating the oscillating member directly by the driving member, I emplo the driving member to so actuate both the escapement wheel of an escapement device and the energy storing means mentioned above, as to maintain the average speed of the escapement wheel constant through the control of the oscillating member. That is, I control the period of the oscillating member by so periodically supplying energy to compensate for the frictional losses as to cause the oscillating member to control the movement of the escapement wheel by means of the escapement lever. For the driving member of the escapement device, I provide a simple electric motor that may be energized from the ordinary commercial power or lighting electric circuit. By means of the arrangement employed in the escape ment device embodylng my invention, the action thereof is entirely independent of any changes in the torque of the driving member, and the average rate of movement of the escapement wheel is, therefore, constant, irrespective of any changes in the condition of the electric circuit to which the driving motor may be connected. Since the rate of movement of the escapement wheel is maintained constant, indicating means may be connected thereto through suitable gears for indicating accurate time intervals. A simple electric motor is employed as a driving member in order that the clock embodying my invention may be used with the ordinary power or lighting circuit.

Fig. 1 is a plan view of the escapement device embodymg my invention; Fig. 2 is a front elevational view of the device shown in Fig. 1; Fig. 3 is a plan view of an electric clock employing the escapement device other end of the escapement lever 5.

shown in Fig. 1; Fig. 4- is a side yiew, partially inelevation and partially in section, of the clock shown in ig. 3, showing the connections thereof to an electric circuit.

An escapement device 1 comprises an oscillating member 2, an actuating spring 3, an escapement wheel 4, an escapement lever 5, and an energy-storing spring 6 that is actuated by a ratchet wheel 7. The ratchet wheel 7 and the escapement wheel 4 are coaxially mounted on a shaft 8 that has a gear wheel 9 also mounted thereon. The gear wheel 9 is adapted to be actuated by a driving member, as will be described later, to rotate the shaft 8. The escapement lever 5 is pivotally mounted on a shaft 10 and has two pallet jewels 11 and 12 mounted on one end and a fork 13 on the other end thereof. The oscillating member 2 and its actuating spring 3 are coaxially mounted on a shaft 14 that also has a table 15 mounted thereon, for supporting a roller jewel 16. As the member 2- oscillates, the table 15 and the roller jewel 16 are so turned by the shaft 14, on which they are mounted as to actuate the escapement lever 5 by engagement with the fork 13. The pallet jewels 11 and 12 are so disposed at the end of the escapement bar 5 that the escapement wheel 4 is permitted to periodically advance one tooth by the action of the oscillating member on the s the shaft 8 rotates, the energy-storing spring 6 is periodically flexed bythe teeth of the ratchet wheel 7. When the apex of a tooth of the ratchet wheel is reached, the spring 6 attempts to drop back to its original position but, at this point a pallet 17, that is mounted on an arm 18 of the escapement lever 5, is in position to so engage a shoe 19, that is mounted on the spring 6, as to prevent the return of the spring 6 toits original position until the shoe 19 is released by the pallet 17. As the oscillating member 2 continues on its path of oscillation, a point is reached at which the movement of the arm 18 and the pallet 17 releases the shoe 19. At this instant, the inclined side or surface of the shoe 19, under the action of the flexed spring 6, so slides from the pallet 17 on the arm 18 as to additionally'actuate the pallet 17. 'Since the arm 18, which supports the pallet 17, is mounted on the escapement lever 5, the force imparted by the shoe 19 to the pallet 17 is transmitted through the arm 18 to the escapement lever 5 and therethrough to the oscillating member 2. Sufficient energy is thus periodically transmitted through the energy-storing spring 6 to the oscillating member 2 to compensate for frictional losses during each cycle of oscillation. A guide 20 is provided for the shoe 19, and an adjusting screw 21 is provided to adjust the amount of movement of the spring 6, which is supported by a stationary block 22. The actuatingspring 3 for the oscillating member 2 has one end thereof secured to the shaft 14 and the other end thereof secured to a stationary member 23.

In Fig.3, a clock 24 comprises an electric motor 25 having a rotatable armature disk 26, an indicating device 27 and the escapement device 1 for controlling the movement of the disk member 26. The electric motor 25 comprises an electromagnet 25 and two windings 28 and 28 which are connected, in series, across a circuit 29. The armature disk member 26, that is actuated by the electromagnet 27, is mounted on a shaft 30 that also has a pinion 31 mounted thereon. The pinion 31 engages the gear wheel 9 of the escapement device 1. The shaft 30 also has a second pinion 32 mounted thereon that engages a gear wheel 33 which is mounted on a shaft 34. The shaft 34 also has a pinion 35 mounted thereon that engages a gear wheel 36 which is mounted on a shaft 37. The gear wheel 36 further engages a gear wheel 38 that is mounted on a shaft 39. The gear wheel 33 also engages a gear wheel 40 that is mounted on a tubular sleeve 41 which is concentric with, and loosely surrounds, the shaft 39. The gear wheel 40 is supported by a supporting member 42. A dial member 43 is concentrically mounted about the shaft 39 and is supported by a stationary member 44. An indicating pointer 45 is adapted to be actuated by the shaft 39, and a second pointer 46 is adapted to be actuated by the tubular shaft 41. The indicating members 45 and 46 rotate above the dial member 43 and cotiperate therewith to indicate time. The circuit 29 is energized from a source 47 of electromotive force and is suitable for supplying energy to a motor 48 or to lamps 49.

When the clock 25 is energized from the circuit 29, the armature disk member 26 is so actuated as to tend to turn the shaft 8 of the escapement device through the pinion 31 and gear wheel 9. The escapement wheel 4, however, is not permitted to turn until released, tooth-by-tooth, through the action of the oscillating member 2 on the escapement lever 5. As one tooth is released by the pallet jewel 11, a following tooth is held by the pallet jewel 12 until the oscillating member returns on its path of oscillation and so actua-tes escapement lever 5 as to permit the tooth held by the pallet jewel 12 to move forward. 'As this tooth moves forward, the-pallet jewel 11 so engages another tooth on the escapement wheel as to prevent any further turning thereby until it is released. Since the actuating force or turning torque is rovided by the rotatable disk member 26 o the motor 25, the oscillating member 2 need merely so control the movement of the escapement wheel 4 as to maintain a constant average rate of speed in the disk member 26. Since the flexible energy-storing spring 6 receives energy from the same actuating disk member 26 and periodically imparts energy to the oscillating member 2, the frictional losses of the escapement device are completely compensated. Since the escapement wheel is permitted to advance tooth-by-tooth in accordance with the period of oscillation of the oscillating member 2, and, since the period of the oscillating member 2 is maintained constant by providing energy for the frictional losses, the average speed of the rotatable disk member 26 is maintained constant, and, therefore, the average rate of movement of the indicating pointers or hands and 46 is maintained constant, and, consequently, time is accurately indicated on the dial 43.

Although I have shown a preferred form of device embodying my invention, I do not limit it to the structure shown, as various modifications may be made therein, such as employing a direct-current motor when desired, without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim as my invention:

1. A controlling device for a clock comprlsing an oscillating member, an escapement device, a ratchet wheel actuated with the escapement device, and energy-storing means controlled by the ratchet wheel and adapted periodically to transmit energy to the oscillating member through a member of the escapement device.

2. A controlling device for a clock comprising an oscillating member, an escapement device embodying an escapement wheel and an escapement lever, a ratchet wheel actuated with the esca ement device, a flexible spring energized y the ratchet 4:. In a controlling device for a clock, the

combination with an oscillating member, an escapement wheel and an escapement lever therebetween, of means actuated in accordance with the escapement wheel and means controlled by said actuated means for periodically actuating the escapement lever to transmit energy thereby to the oscillating member.

5. In a controlling device for a clock, the combination with an oscillating member, an escapement wheel and an escapement lever therebetween, of a ratchet wheel controlled in accordance with the escapement wheel, a resilient member periodically stressed by the ratchet wheel and then released to transmit the energy stored therein to the oscillating member through the escapement lever.

6. In a controlling device for a clock, the combination with an oscillating member, an escapement wheel and an escapement lever therebetween, of a cam member disposed on the escapement lever and means periodically stressed in accordance with the movement of the escapement wheel for actuatin the'lever by contactive engagement with t e escapement lever.

In testimony whereof, I have hereunto subscribed my name this 21st day of Jlan ua .1920. ry LEO DORFMAN 

